Turbine rotor-jet nozzle assembly



Aug. 1, 1967 V. D. BAKER ETAL TURBINE ROTOR-JET NOZZLE ASSEMBLY Filed March 22. 1965 2 Sheets-Sheet l ATTORNEY A118- 1, 1967 v. UBAKER ETAL. 3,333,818

TURBINE KOTOR-JET NOZZLE ASSEMBLY 2 Sheets-Sheet 2 Filed March 22. 1965 v fura/7 AT TORNE Y United States Patent O ABSTRACT OF THE DISCLOSURE A turbine rotor with rearward extensions on the blade platforms which form the base wall for a jet nozzle. The turbine rotor has a concave wall secured to it which engages the downstream edges of the base wall to decrease weight and improve exhaust flow. The concave wall also cooperates with the walls to retain them on the turbine rotor.

This invention relates generally to a turbine-jet nozzle assembly having an integrated turbine rotor .and jet nozzle base wall.

It is conventional practice to provide a base wall or tail cone behind a turbine rotor in order to improve gas flow through the jet nozzle and increase its efliciency. These base walls are usually a one-piece wall of substantial length suspended in the jet nozzle by a plurality of struts. Gas turbine lift engines designed for vertical installation in aircraft are of necessity of minimum axial length with the result that the turbine-jet nozzle section is very short and the conventional base wall nozzle is not particularly suited for it.

It is, therefore, an object of the present invention to provide a jet nozzle base wall particularly suited for a vertically installed lift type gas turbine engine.

Another object is to provide a turbine-jet nozzle assembly having a `base wall particularly suited for a vertical lift type engine with substantially the same eiciency as the conventional larger types.

Another object is to provide a turbine-jet nozzle assembly in which the turbine rotor and jet nozzle base wall have been integrated to provide maximum eciency in a minimum axial length.

Another object is to eliminate the necessity for support struts and the design problems associated therewith.

With these and other objects in view, as will hereinafter more fully appear, and which will be more particularly pointed out in the appended claims, reference is now made to the following description taken in connection with the accompanying drawings in which:

FIGURE l is a transverse section of a portion of a gas turbine engine provided with a turbine-jet nozzle in accordance with the present invention.

FIGURE 2 is a perspective view of the turbine rotor assembly of FIGURE 1.

FIGURE 3 is a perspective view of an individual turbine blade.

FIGURE 4 is a section View taken substantially along the line 4 4 of FIGURE l looking in the direction of the arrows.

Referring now to FIGURE 1, there is shown a portion of a gas turbine engine including a casing 12, an annular member 14 which is curved and reversed at one end and Patented Aug. 1, 1967 a C-shaped annular wall 16 which straddles the curved and reversed end of member 14. The above members are connected to form a combustor inlet 13 and outlet 15 with a combustor chamber 17 mounted therebetween. Fuel nozzles 18 are mounted at the junction of casing 12 and member 14 and have the tip extending into the combustor 17. The exit portion of the combustor outlet 15 serves as the turbine inlet and is provided with radially extending guide vanes 20.

A housing 22 is mounted concentrically within member 16 by struts (not shown) to support a bearing 26 in which is journaled an integral turbine-shaft assembly indicated generally at 24. An exhaust duct 28 circumferentially abuts the middle of member 14 and is retained against a shoulder thereof by tabs 31 on the exhaust duct 28 which are rotated into engagement with mating tabs 33 on the member 14. Straps 30 on the duct 28 are connected to the casing by the fuel nozzle 18 to prevent rotation of the duct 28 and disengagement of the tabs 31 and 33. The environmental structure of bearing 26 is part of the bearing lubrication system, the details of which are immaterial.

Referring now to FIGURES 2 and 3, the turbine-shaft assembly 24 is shown in greater detail. The assembly comprises an integral hollow shaft and rotor wheel 32 which has a plurality of circumferentially spaced axial slots 34 in which a plurality of blades 36 are mounted to form the turbine rotor. FIGURE 3 shows a single lblade 36 which has a conventional dovetail foot 38 adapted to mate with slots 34. Foot 38 is provided with forward and rearward tangs 40 and 42 respectively, which are L-shaped in cross-Section so as to provide an axial space between the radial portion thereof and the rotor wheel 32 when the blade 36 is assembled thereto. A stalk 56 spaces platform 44 radially outwardly from foot 38. The front edge 46 of the yplatform is grooved and adapted to form a labyrinth seal with the circumferential edge 48 on wall 16. The rear edge yof platform 44 has an integral extension 50 which is coextensive with the platform 44 and terminates in an inwardly extending lip 52. An arcuate web 70 extends from the rearward edge of stalk 56 and supports the rearward portion of platform 44 and extension 50. The blade is shown as having a pair of inlets 54 in the stalk 56 which communicate with the hollow airfoil 60 to provide a passage for the iiow of cooling air through the blades. However, this invention is equally applicable to non-cooled or solid blades.

When the blades are assembled to the wheel 32, the front and rear tangs 40 and 42, respectively, will straddle the wheel' and the platforms will abut adjacent platforms to form an annular ring or shroud with the rear extensions 50 forming an annular converging base wall 68. An arcuate annular member 72 lies adjacent the inner edge of webs 70. The outer circumferential edge of member 72 is castellated with each of the tangs 74 formed by the castellations disposed in mating slots 76 formed in the lip 52 of blade platform extensions 50. The one end of the member 72 is thus connected to the end of the annular base wall 68 while relative movement between the parts is permitted so as to minimize the transfer of stress therebetween. Adjacent the opposite circumferential edge of the member 72 is an integral annular r L-shaped flange 78 which has its radial leg disposed in the annular space lbetween the turbine wheel 32 and the radial portion of the rear tang 42. This intert between the flange 78 and the rear tangs 42 prevents the blades 36 from being withdrawn axially frontwardly from' the wheel 32.

A circumferential backplate 80 with a cupped center 82 is secured to the turbine Wheel 32 -by means of a fitting 84 which is threadably received in a spacer 86 welded to the turbine wheel 32 at 87. The outer circumferential edge of the backplate 80 carries a plurality of pins 89 which are received in slots 91 adjacent the inner circumferential edge of the member 72. The pins 89 fit in the apertures 91 in a manner which permits joint slippage. The backplate 80 is thus mounted on the turbine wheel 32 and is also connected to the member 72 in a manner to minimize stress transfer to the thin backplate 80. Together, the backplate 80 and element 72 form a concave wall abutting the trailing edge of the annular base wall 68.

In assembling the turbine rotor assembly 24, the backplate 80 and element 72 are first assembled. The individual blades 36 are then spaced around the periphery of member 72 with the radial portions of rearward tangs 42 disposed in the groove formed by the L-shaped ange 78. With the blades thus spaced, the turbine wheel is axially slid into place so the feet 38 are received in the slots 34. Next, individual hog rings 94 are closed around each of the forward tangs 40 to prevent the blades 36 from being withdrawn axially rearwardly from the wheel 32. Thus, the turbine wheel assembly shown generally at 24 is completed and is then ready to be assembled into its environment as shown in FIGURE l. When the turbine assembly 24 is rotatably mounted in the housing 22, the blades 60 will lie just downstream of the guide vanes 20 and the annular base wall 68 will form an annular jet nozzle 92 with the exhaust duct 28. Thus it can be seen that we have invented an integrated turbinejet nozzle having a maximum elliciency in a minimum axial length.

It should be understood, of course, that the foregoing disclosure relates only to -a preferred embodiment of the invention and that numerous modifications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

We claim:

1. A turbine rotor comprising in combination:

a rotor wheel,

a plurality of circumferentially spaced blades secured to said wheel,

a platform on each of said blades,

an integral axial rearward extension on each of said platforms substantially coextensive therewith, each of said platforms abutting platforms on adjacent blades whereby said extensions form an annular base wall for an annular jet nozzle,

a web extending radially inwardly from each platform, said webs having a radially inward concave edge, and

an annular concave wall mounted on said rotor and abutting said web edges, said concave wall having an outer circumferential edge engaging the free end n of said base wall.

2. A turbine jet nozzle assembly comprising in cornbination:

an annular duct,

a rotor Wheel rotatably mounted in said duct,

a plurality of circumferentially spaced blades securedY to said wheel,

a platform on each of said blades abutting the platform on the 'blades adjacent each of said blades, an integral axial rearward extension on each of said platforms substantially coextensive therewith, each -ofsaid platforms abutting platforms on adjacentblades whereby said extensions form an annular base wall,

a web extending radially inwardly from each platform, said webs having a radially inward concave edge,

an annular concave wall mounted on said rotor and abutting said web edges, said concave wall'having an outer circumferential edge engaging the free end of said base wall, and

an annular jet nozzle dened by a portion of said duct and said base wall.

3. A turbine rotor comprising in combination:

a rotor wheel,

a plurality of circumferentially spaced blades secured to said wheel,

a platform on each of said blades,

an integral axial rearward extension on each of said platforms substantially coextensive therewith, each of said platforms abutting platforms on adjacent blades whereby said extensions form an annular base wall for an annular jet nozzle,

an annular concave wall mounted on said rotor having an outer circumferential edge engaging the free end of said base wall, and

a backplate mounted on said rotor having an outer circumferential edge movably secured to said concave wall.

4. A turbine jet nozzle assembly comprising in combination:

an annular duct,

a rotor wheel rotatably mounted in said duct,

a plurality of circumferentially spaced blades secured to said wheel,

a platform on each of said blades abutting the platform on the blades adjacent each of said blades,

an integral axial rearward extension on each of said platforms substantially coextensive therewith, each of said platforms abutting platforms on adjacent blades whereby said extensions form an annular base wall,

a web extending radially inwardly from each platform, said webs having a radially inward concave edge,

an annular concave wall mountedV on said rotor and abutting said web edges, said concave wall having an outer circumferential edge engaging the free end of said base wall,

a backplate mounted on said rotor having an outer circumferential edge movably secured to said concave wall, and

an annular jet nozzle defined by a portion of duct and said base wall.

5. A turbine rotor comprising in combination:

a rotor wheel having circumferentially spaced axial slots,

a plurality of blades having feet mating with said slots and disposed therein,

rearward tangs on said feet,

means to prevent axial rearward movement of said blades,

platforms on said blades spaced radially outwardly from said feet,

integral rearward extensions on said platforms, said` platforms abutting adjacent platforms whereby said extensions form an annular base wall for an annular jet nozzle,

an annular concave member having an outer circumferential edge vengaging the free end of said base wall, and

means on said member to engage said rearward tangs to prevent axial forward movement of said blades said means to prevent axial rearward movement of said blades,

platforms on said blades spaced radially outwardly from said feet,

integral rearward extensions on said platforms, said platforms abutting adjacent platforms whereby said extensions form an annular base wall for an annular jet nozzle,

an annular concave member having an outer circumferential edge engaging the free end of said base wall,

an L-shaped flange adjacent the inner circumferential edge of said member, said flange engaging said rearward tang to prevent axial forward movement of said blades whereby said blades are secured to said 15 rotor, and

a backplate mounted on said rotor having an out circumferential edge movably secured to the inn circumferential edge of said annular member.

References Cited UNITED STATES PATENTS 2,656,146 10/1953 Sollinger. 3,008,689 11/1961 Morley et al 253-1 FOREIGN PATENTS 201,150 1/1956 Australia.

MARTIN P. SCHWADRON, Primary Examiner.

EVERETTE A. POWELL, IR., Examiner. 

1. A TUBINE ROTOR COMPRISING IN COMBINATION: A ROTOR WHEEL, A PLURALITY OF CIRCUMFERENTIALLY SPACED BLADES SECURED TO SAID WHEEL, A PLATFORM ON EACH OF SAID BLADES, AN INTEGRAL AXIAL REARWARD EXTENSION ON EACH OF SAID PLATFORMS SUBSTANTIALLY COEXTENSIVE THEREWITH, EACH OF SAID PLATFORMS ABUTTING PLATFORMS ON ADJACENT BLADES WHEREBY SAID EXTENSIONS FORM AN ANNULAR BASE WALL FOR AN ANNULAR JET NOZZLE, 